When the seven dwarves run scared down the stairs and out of the door, Dopey pulls the handle of the door from the inside until it breaks out and falls away. The next scene when the dwarf opens the door, the handle is there again.

When making this movie, Walt Disney turned the script into a comic at first and they used these "comic strips" to move around shots and scenes, replace things and generally see what would work or not. This technique is now known as storyboarding and pretty much every single movie production uses it.